DAYTON, Ohio – Hoping to woo disaffected women and charm conservatives, John McCain yesterday tapped a virtual political unknown as his running mate – Alaska Gov. Sarah Palin, a mom of five and crack-shot hunter who is sure to shake up the presidential race.

The surprising choice aims to peel away Hillary Rodham Clinton supporters who were disappointed that Barack Obama didn’t pick her as his No. 2.

Describing herself as an “average hockey mom” and former PTA member, a feisty Palin wasted no time in making a gender appeal after she and McCain got a rousing welcome from 15,000 supporters in the Nutter Center arena.

“The mission is clear. The next 67 days I’m going to take our campaign to every part of our country and our message of reform to every voter of every background in every political party or no party at all,” said Palin, joined on stage by her husband and four of her five kids, who range in age from 5 months to 18 years.

“Politics isn’t just a game of competing interests and clashing parties,” she said.

It was the largest crowd to show up at any McCain campaign event.

“She’s exactly who I need; she’s exactly who this country needs to help me fight the same old Washington politics of me first and country second,” McCain told the roaring throng.

Noting it was the 88th anniversary of women’s gaining the right to vote, Palin praised Clinton and former Democratic vice-presidential candidate Geraldine Ferraro as pioneers for women’s rights. She said she also has spent her life challenging the “good-old-boy network.”

“Hillary Clinton left 18 million cracks in the highest, hardest glass ceiling in America. But it turns out the women of America aren’t finished yet, and we can shatter that glass ceiling once and for all,” she said to rousing applause.

McCain made his bold selection six days after Obama named Sen. Joe Biden as his No. 2 pick.

Obama, 47, picked a 65-year-old running mate with long experience. McCain, who turned 72 yesterday, chose a 44-year-old running mate who until recently was the mayor of small-town Wasilla, Alaska.

The selection itself was one of the better-kept secrets in politics – one that remained sealed until about two hours before its announcement.

Palin first caught McCain’s attention at a National Governors Association meeting in Washington last February, his campaign said. The pair spoke by phone last Sunday – McCain at home in Phoenix, Palin at the Alaska State Fair – though the campaign had been in contact with her as part of the selection process.

Palin and an aide flew to Phoenix on Wednesday. The next day, she met with McCain and his wife, Cindy, and was formally “invited” to be McCain’s veep.

“I know that when Senator McCain gave me this opportunity, he had a short list of highly qualified men and women, and to have made that list at all, it was a privilege,” she said. “And to have been chosen brings a great challenge. I know that it will demand the best that I have to give, and I promise nothing less.”

At the rousing announcement, McCain declared she was the right choice, noting her meteoric political rise and her fearlessness on battling special interests and corruption.

“I spent the last few months looking for a running mate who could shake up Washington,” he said. “I have found the right partner . . . She knows where she comes from, and she knows who she works for.”

In a statement, Obama and Biden hailed Palin as an “admirable person who will add a compelling new voice to the campaign.”

Palin became the youngest governor in Alaska’s history after defeating incumbent Republican Gov. Frank Murkowski in the 2006 primary – building her career in large measure by challenging fellow Republicans.

She and her commercial-fisherman husband, Todd, have been married 20 years. She proudly mentioned that their eldest son, Track, who is in the Army, enlisted last Sept. 11. She said he would be assigned to Iraq this Sept. 11.

Her youngest son, 4-month-old Trig, has Down syndrome.

Palin has pushed for tax cuts and spending restraint, is pro-life and a staunch supporter of gun rights. As a girl, she went hunting with her dad in the wee hours before school.

She also strongly supports offshore oil drilling, including in the Alaskan National Wildlife Refuge. McCain has opposed drilling for oil in ANWR.

McCain stressed that Palin has fought to make American more independent from foreign oil. He also praised her for vetoing spending bills as governor and putting a stop to the “bridge to nowhere” that would have cost taxpayers $400 million.

“I’ve championed reform to end the abuses of earmark spending by Congress,” she said.